Older adults are at increased risk for diabetes but there is controversy regarding prognosis in prediabetes and diabetes, appropriate screening and treatment targets, and how best to reduce cardiovascular risk and prevent cognitive and physical impairment, especially in persons aged 70 years or higher. The Atherosclerosis Risk in Communities (ARIC) Study is an ongoing, community-based study of 15,792 participants originally recruited in 1987-1989. For over 25 years, ARIC investigators have conducted detailed assessments of cardiovascular disease and its risk factors including diabetes. At the most recent visit 5 (2011- 2013), the mean age of participants was 75 years, 23% were black, and 33% of participants had diagnosed diabetes. New visits in ARIC are planned from 2016 to 2019. This application is a request for funding of an approved ARIC ancillary study to add key diabetes-related measures to the upcoming visits. Aims: 1) Quantify the risk of incident prediabetes and diabetes in older black and white adults using multiple biomarkers; 2) Characterize the risk of clinical microvascular and macrovascular outcomes in older adults with diabetes, paying particular attention to differences in risk in older onset compared to middle-aged onset diabetes; 3) Characterize the association of prediabetes with risk of clinical and subclinical and clinical outcomes in older adults including physical and cognitive dysfunction; 4) Identify risk factors for hypoglycemia in older adults with diabetes and its associations with cardiovascular risk, mortality, and cognition. We will also evaluate the associations of hyperglycemia and hypoglycemia with neuropathy, care practices, diabetes awareness and treatment satisfaction. Design and Methods: We will collect biospecimens from over 4,000 ARIC participants at the upcoming visits and conduct measurements of standard and nontraditional biomarkers of hyperglycemia, kidney disease, and cardiovascular disease. We will also conduct new assessments of hypoglycemia, neuropathy, preventive care practices, and diabetes treatment satisfaction. The proposed assessments will add over 5 years of additional follow-up (from visit 5) and will take advantage of ongoing surveillance for all hospitalizations, adjudicatin of cardiovascular and other events, and linkage to Medicare data. Significance: This competing renewal is designed to address long-standing controversies in the field and inform our understanding of the burden and clinical implications of prediabetes and diabetes in older adults. We will shed light on prognosis in heterogeneous glycemic subgroups and the performance of different markers of hyperglycemia. The data generated will provide evidence to assist clinicians in formulating more specific recommendations regarding testing, prognosis, and race- and age-related differences in risk associated with diabetes in older age. Results of this study will have direct relevance to clinical practice and inform strategies for the management of diabetes in older adults.